A fuel injector can be used to inject high pressure fuel into a cylinder of a combustion engine. Specifically, a tip of the fuel injector has one or more small orifices disposed therein and, as the high pressure fuel is directed into the fuel injector, it passes to the cylinder by way of these orifices. To enhance operation of the combustion engine, the orifices are precisely formed to have a particular profile and opening diameters.
One way to produce high-precision orifices is through laser machining. Specifically, laser machining involves the use of a laser to melt, vaporize, and/or ablate micro-craters within the fuel injector in a controlled fashion. In some situations, laser machining of fuel injectors can benefit from the use of a delivery media. For example, in the fuel injector application, because of small clearances within the fuel injector, it can be difficult to access the tip area of the injector for machining from the inside. In these situations, the delivery media can be inserted into the fuel injector and used to deliver a laser beam from the laser into the injector tip for machining from the inside. When using a delivery media in a laser machining application, care should be taken to properly position, orient, and focus the laser beam exiting the tip end of the delivery media such that the resulting feature is positioned properly and has a desired profile.
One example of a system that uses a delivery fiber in conjunction with laser machining is disclosed in U.S. Pat. No. 6,888,097 (the '097 patent) issued to Batarseh on May 3, 2005. In particular, the '097 patent discloses an apparatus for perforation of well bore walls. The apparatus includes a flexible fiber optic cable having a laser input end and a laser output end. A laser source is operably connected to the laser input end, and a laser head is connected to the laser output end. The laser head includes control components for controlling a laser beam characteristic. These control components include a movable mirror that reflects the laser beam laterally outward from the laser head, and a lens that is adjustable to enable focusing of the laser beam in the axial direction of the fiber optic cable. Laser head control elements for controlling the motion and location of the laser head within the well bore are operably connected to the fiber optic cable along a length of the cable. With this configuration, the fiber optic cable can be lowered into an existing well bore, and a laser beam can be directed through the cable and reflected off of the mirror to drill holes along a length of the well bore walls.
Although the apparatus described in the '097 patent may enable laser machining in a difficult-to-access area, its use and accuracy may be limited. Specifically, because of the size and location of the laser head control elements, the configuration described in the '097 patent may be of little use in manufacturing components smaller than a well bore where tight clearances may be an issue. In addition, the use of the mirror to reflect the laser beam may result in poor machining location accuracy and reduced durability in high production applications. Further, the flexibility of the fiber optic cable may reduce repeatability of the machining process.
The present disclosure is directed to overcoming one or more of the shortcomings set forth above and/or other problems of the prior art.